The Awkward Alarm

A rather annoying little noisemaker.

Assembly suggestions

Design Files

The design tarball includes all design files, including code, board and schematic (in Eagle format), gerbers, makefiles, et cetera. As should be clear from the Makefile, building the code requires SDCC. It should also be possible to use the SiLabs IDE as long as you use SDCC with it, though I haven't tested compilation in the IDE.

I have used both ec2drv and the SiLabs IDE to program the microcontroller on the board; both should work without an issue. See above for information on connecting the board to the debug adapter. You should also be able to program using the much cheaper SiLabs ToolStick, though I haven't tried it.

BOM

Note: Any appropriate panel mount potentiometer or momentary switch can be substituted for the corresponding components below. The speakers listed below are only a suggestion; this circuit can drive most 4 or 8Ω speakers, but be sure the speaker's power rating is sufficient.
ComponentValueQuantitySize/TypeDigi-Key P/N
Resistor220Ω10402311-220JRCT-ND
Resistor3.3kΩ20402311-3.3KJRCT-ND
Resistor15kΩ10402311-15KJRCT-ND
Resistor68kΩ20402311-68KJRCT-ND
Potentiometer50kΩ16mmCT6EP503-ND
Capacitor470pF20402 X7RPCC471BQCT-ND
Capacitor0.1uF100402 Y5V490-1327-1-ND
Capacitor4.7uF30402 X5RPCC2475CT-ND
Capacitor10uF50805 Y5V445-3458-1-ND
Capacitor100uF27343-31 Tantalum718-1057-1-ND
Inductor33uH1DR125513-1528-1-ND
Inductor47uH1NR6028 or DR73587-2104-1-ND
DiodeSS121SMA SchottkySS12FSCT-ND
MOSFETFDT457N1SOT-223 NMOSFDT457NCT-ND
Dual BJTMMDT39461SOT-363 NPN/PNPMMDT3946-FDICT-ND
H-BridgeSI998618-SOICSI9986DY-T1-E3CT-ND
MicrocontrollerC8051F410132-LQFP336-1318-ND
SwitchSPST (NO)15mmCKN9102-ND
Speaker (opt 1)4W, 8Ω140mm x 40mm102-1305-ND
Speaker (opt 2)2W, 8Ω128mm round102-1559-ND
Case (opt 1)RL6105180mmx60mmx30mmHM1068-ND
Case (opt 2)RL6115180mmx60mmx40mmHM1069-ND
Battery caseSBH-431-1A13xAAASBH-431-1A-ND

Questions? Comments? <rsw@jfet.org>
Copyright © 2009 by Riad S. Wahby. This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/).
$Id: index.html 493 2009-10-27 18:56:04Z rsw $